In the field of soft tissues, such as facial tissue and bath tissue, it is well known that the application of polysiloxanes to the surface of the tissue can impart an improved surface feel to the tissue. However, polysiloxanes are also known to impart hydrophobicity to the treated tissue. Hence, it is difficult to find a proper balance between softness and wettability, both of which are desirable attributes for tissue, particularly bath tissue.
It has now been discovered that the wettability of a tissue can be improved with minimal negative impact on the surface feel of the tissue by treating one or both outer surfaces of the tissue with a particular group of hydrophilically-modified amino-functional polysiloxanes. More specifically, suitable polysiloxane structures have one or more pendant groups and/or one or both terminal groups which contain an amine derivative. The general structure of the hydrophilically-modified amino-functional polysiloxanes of this invention is as follows: 
wherein
R1 is a C1 to C8 straight chain, branched, cyclic alkyl radical;
R2, R3, and R4 are independently a C2 to C10 straight chain, branched, cyclic, unsubstituted or substituted alkylene diradical;
m=0 to 10,000;
n=20 to 100,000;
r=1 to 10,000;
s=0 to 10,000;
t=0 or 1;
xe2x80x9cAxe2x80x9d is a N R5 R6, a (N R7 R8 R9)+ Xxe2x88x92, a OCOR8R9; a Oxe2x80x94SO3R1; a PO3 R11 R12, or a COOR14 radical;
when m=0, R5 and R6 are independently a radical of CO R15, COO R15, CON R15 R17, COR16xe2x80x94COR17; or R18xe2x80x94COOR17;
when m greater than 0, R5 and R6 are independently a radical of hydrogen, C1 to C8 alkyl, CO R15, COO R15, CONR15 R17, COR16xe2x80x94COR17 or xe2x80x94R18xe2x80x94COOR17;
R7, and R8 are independently a C1 to C6 alkyl radical;
R9 is a C1 to C30 straight chain, branched, substituted or unsubstituted alkyl radical, or a
SO2 PhR10 where Ph is a phenyl group;
R10 is a C1 to C30 straight chain, branched, substituted or unsubstituted alkyl radical;
xe2x80x9cXxe2x80x9d is a halide, a sulfate or other counter ion;
R11 and R12, are independently a C1 to C6 alkyl radical;
R14 is a hydrogen, a C1 to C30 straight chain, branched, substituted or unsubstituted alkyl radical;
R15 and R17 are independently a C1 to C30 straight chain, branched, substituted or unsubstituted alkyl radical;
R16, R18 are independently a C1 to C8 ethylene diradical; and
xe2x80x9cBxe2x80x9d is a hydrogen, an amino acid or an aminoacid derivative, a C1 to C6 straight chain, branched, cyclic alkyl radical or independently a radical of xe2x80x9cAxe2x80x9d.
Representative species within the foregoing general structure include the following: 
The derivitized amino-functional polydimethylsiloxanes described above can be applied to the tissue web alone or in conjunction with other chemicals, such as bonders or debonders. They can be applied to the tissue web, particularly an uncreped throughdried web, by spraying or printing. Rotogravure printing of an aqueous emulsion is particularly effective. Add-on amounts can be from about 0.5 to about 15 dry weight percent, based on the weight of the tissue, more specifically from about 1 to about 10 dry weight percent, still more specifically from about 1 to about 5 weight percent, still more specifically from about 2 to about 5 weight percent. The distribution of the deposits of the derivitized amino-functional polydimethylsiloxanes is substantially uniform over the printed surface of the tissue, even though the surface of the tissue, such as in the case of uncreped throughdried tissues, may be highly textured and three-dimensional.
The Wet Out Time (hereinafter defined) for tissues of this invention can be about 15 seconds or less, more specifically about 10 seconds or less, still more specifically about 6 seconds or less, still more specifically about 5 seconds or less, still more specifically from about 4 to about 8 seconds. As used herein, xe2x80x9cWet Out Timexe2x80x9d is related to absorbency and is the time it takes for a given sample to completely wet out when placed in water. More specifically, the Wet Out Time is determined by cutting 20 sheets of the tissue sample into 2.5 inch squares. The number of sheets used in the test is independent of the number of plies per sheet of product. The 20 square sheets are stacked together and stapled at each corner to form a pad.
The pad is held close to the surface of a constant temperature distilled water bath (23+/xe2x88x922xc2x0 C.), which is the appropriate size and depth to ensure the saturated specimen does not contact the bottom of the container and the top surface of the water at the same time, and dropped flat onto the water surface, staple points down. The time taken for the pad to become completely saturated, measured in seconds, is the Wet Out Time for the sample and represents the absorbent rate of the tissue. Increases in the Wet Out Time represent a decrease in absorbent rate.
The xe2x80x9cDifferential Wet Out Timexe2x80x9d is the difference between the Wet Out Times of a tissue sample treated with a derivitized amino-functional polydimethylsiloxane and a control tissue sample which has not been treated. The Differential Wet Out Time, for purposes of this invention, can be about 10 seconds or less, more specifically about 5 seconds or less, still more specifically about 3 seconds or less, still more specifically about 2 seconds or less, and still more specifically about 1 second or less.
The ratio of the Differential Wet Out Time to the add-on amount of the derivitized amino-functional polydimethylsiloxane can be about 3 seconds per weight percent or less, more specifically about 1 second per weight percent or less, still more specifically about 0.5 second per weight percent or less.
Tissue sheets useful for purposes of this invention can be creped or uncreped. Such tissue sheets can be used for facial tissues, bath tissues or towels. They can have one, two, three or more plies. The basis weight of the tissue product can be from about 25 to about 50 grams per square meter. If used for bath tissue, a single ply tissue having a basis weight of from about 30-40 grams per square meter is particularly suitable.